We recommend zero deck height pistons 100% unless you need a much lower compression for forced induction. I dont know of any cams out there that will interfere with even a flat top piston for a 258. We have done all the ring packages for the bore size on the 258/232/242 (4.0) 1/16 1/16 3/16 is not an issue.
I design and build parts for AMC V8 racing engines, street or trail. If you have a specific performance question please PM me I will be glad to give you 100% accurate information.
Big ones line up...little ones get in a group